Device for heating and vaporizing a vaporizable module

ABSTRACT

A vaporizing device including a heating unit having a pair of electrical connector terminals staked to a substantially rigid substrate having a serpentine resistance type heating element printed thereon and electrically connected to the terminals. An insulating conformal layer coats the heating element, and wicks into the interstices of the region between said electrical terminals and the openings in the substrate receiving the terminals to significantly enhance the structural strength of the device. This provides an inexpensive and yet sturdy and rugged vaporizing device which may be discarded after each use.

This is a DIVISION of Application Ser. No. 08/213,958, filed Mar. 16,1994.

FIELD OF THE INVENTION

The present invention relates a heating device for heating a vaporizablematerial and to a method for producing same and more particularly to amethod for producing a heating device which, in addition to being arugged and sturdy unit, is inexpensive and may be discarded after eachuse.

BACKGROUND OF THE INVENTION

Deodorants and insect and pest repellants have become quite popular foruse in deodorizing and/or protecting rooms, including bathrooms, ofhomes, hospitals, factories, office buildings and the like. In additionto deodorizers and repellants employing wicks which are exposed to theair within a room being deodorized, and sprays, such as aerosol sprays,electrically heated deodorizers and repellant devices have recently beendeveloped as a very popular alternative for the aforementioneddeodorizers.

A variety of such devices are presently in the marketplace and typicallycomprise a housing containing a vaporizable module. A pair of electricalterminals project from a rear surface of the housing for electricalconnection into a standard wall socket typically providing 115 volt a.c.power. The a.c. source energizes a resistance heater for heating a scentmodule, for example, to release a pleasant aroma or essence into theatmosphere so long as the heater element is energized.

When a scent module is dissipated, it is discarded and replaced with anew module. Scent modules are available for purchase as refills,enabling the heating element unit to be used over and over again.

Conventional devices have a number of disadvantages. Firstly, theheating device housing must be provided with a releasable closure deviceto permit access to the scent module compartment for removal andreplacement of a scent module, causing the structure of the device to berelatively complex and bulky and further causing the unit to protrudeaway from the wall containing the electrical socket into which theheating unit is inserted, thus presenting a potential obstruction topassersby as well cleaning apparatus (brooms, sweepers, vacuum cleanersand the like). In addition, the complex structure which requires moving,or at least movable parts, significantly increases production costs. Inaddition, substantially unlimited reuse of the heating devicesignificantly contributes to the possible deterioration and even faultyand possible dangerous operation of the heating device. Users aretypically unaware of deterioration or weakening of the device, therebysubjecting the user to potential harm.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is characterized by comprising a novel heatingdevice structure and a method for producing such heating devices whichare characterized by comprising a design that can be produced at a costwhich is significantly less than the cost of producing conventionalheating devices thereby enabling heating devices produced according tothe method of the present invention to be discarded after thevaporizable capsule housed therein is exhausted, i.e. leading to thedevelopment of a heating device which may be discarded after exhaustionof a block or module, if desired.

The heater assembly of the present invention comprises a polymerresistor element printed upon one surface of an insulating substrateutilizing conventional printed circuit techniques. The resistor-typeheating element is electrically connected to an electrical power sourceby means of a pair of metal blades or terminals which are insertedthrough openings provided in the insulating substrate, which blades haveprojections that are mechanically crimped to the substrate in order tomake good electrical contact with the heating element.

The crimping operation is followed by the step of coating the resistorelement with an insulating resin to protect the surface of the resistorelement and the exposed surface of the crimped metal portion of theterminals which protrude through the substrate. In one preferredembodiment, a housing is molded about the heater assembly andvaporizable module, effectively eliminating any moving or movable parts.The conformal layer, in addition to providing an insulating coating forthe heater element and crimped projections, wicks into the intersticesbetween the openings in the substrate and the blades to significantlyenhance the resistance to atmospheric corrosion between the crimpedprojections and the substrate which enhances the integrity of theelectrical path between the electric terminals and the resistance-typeheater element as well as imparting structural strength to the unifiedsubstrate and electrical blades to significantly enhance the safe use ofthe scent or repellant emitting device.

With the need for a removable and replaceable cover eliminated, themolded package becomes quite compact and has an extremely low profile,yielding a housing which projects outwardly from a wall socket by adistance which is significantly less than those encountered inconventional electrical scent emitting devices.

In a preferred embodiment, the scent module is provided with flutes orgrooves which cooperate with slot-like openings within the housing toprovide a chimney effect for the emission of the airborne vapor.

In an alternative embodiment, the heating element may be snap-fittedinto a slot-like receptacle within the housing to lock the heatingelement subassembly therein. The housing cover is snap-fittingly mountedthereto after insertion of the vaporizable module.

OBJECTS OF THE INVENTION

It is therefore one object of the present invention to provide a novelelectrical-type vaporizing device incorporating a heating elementsubassembly of significantly enhanced mechanical and electricalstrength, and a method for producing same.

Still another object of the present invention is to provide a low cost,electrical-type vaporizing device and a method for producing same andwhich permits the production of such units at significantly reducedcost, enabling the production of units capable of being discarded afterone use.

Still another object of the present invention is to provide a novelelectrical-type vaporizing device incorporating a heater element formedon an insulating substrate through the employment of printed circuittechniques and connected to a pair of electrical blades or terminalsadapted for insertion into a conventional two terminal electric outletand further including a conformal protective layer of a suitable polymerwhich provides insulation for the resistance-type heating element andexposed surfaces of crimped portions of the electrical terminals andwhich further wicks into the interstices between the substrate and theterminals to impart significant structural strength to the assembly.

Still another object of the present invention is to provide a method forproducing vaporizing devices of the type described above.

Still another object of the present invention is to provide a novelelectrical-type vaporizing device comprising a one-piece, permanentlysealed housing to prevent tampering either during or after use thereof.

Still another object of the present invention is to provide a novelelectrical-type vaporizing device utilizing a fluted vaporizable modulewhich cooperates with elongated slots provided in the housing of thevaporizing unit to provide a "chimney" effect.

BRIEF DESCRIPTION OF THE FIGURES

The above, as well as other objects of the present invention will becomeapparent when reading the accompanying description and drawings inwhich:

FIG. 1 is a perspective view of a heating device subassembly designed inaccordance with the principles of the present invention.

FIG. 2 show a sectional view of the mechanical and electrical connectionbetween the insulating substrate and resistor-type heating element onthe one hand and the electrical terminal on the other hand, looking inthe direction of arrows 2--2 of FIG. 1.

FIG. 2a shows an elevational view, partially sectionalized, of anotheralternative electrical terminal which may be used in the heating devicesubassembly of the present invention.

FIG. 3 shows a perspective view of a molded housing for use with theheating device subassembly of FIG. 1.

FIG. 3a shows a rear view of the housing of FIG. 3 and FIG. 3b shows asectional view of one side wall of the housing of FIG. 3a looking in thedirection of arrows 3b--3b and further showing the manner in which thesubstrate of the heating device subassembly mounts thereon.

FIG. 3b is a detailed view showing the manner in which a housing sidewall supports a marginal edge of a substrate.

FIG. 4 shows a simplified, exploded, perspective view of the housingcover, heater unit subassembly and scent module forming the scentemitting device of the present invention.

FIG. 5 shows a plan view of a substrate on which a plurality of heatingunit subassemblies have been formed and which is useful in describingthe techniques for simultaneously producing a plurality of suchassemblies.

FIGS. 6a, 6b and 6c are views showing the manner in which a heating unitand a scent modular are installed within a housing.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF

FIGS. 1 and 2 show a heating element subassembly 10 designed inaccordance with the principles of the present invention and comprised ofa substantially rectangular-shaped insulating substrate 12 which ispreferably formed of the same material utilized to produce printedwiring boards. The shape of the substrate 12 is not critical, the onlycriteria being that the substrate is large enough to accommodate theheating element and the terminals 16. A resistor-type heater element 14is printed on one major surface of the insulating substrate 12 utilizingconventional techniques for creating such patterns on printed circuitboards and the like. The resistance-type heating element is preferablycomprised of a polymer resistor element printed on the surface of theinsulating substrate and is comprised of a first serpentine portion 14ajoined to a second pair of serpentine portions 14b by substantiallystraight elongated pattern portions 14c and 14d. The facing ends of theadjacent, inner ends of the serpentine portions 14b extend downwardlyand outwardly and terminate in a pair of terminal pads 14e and 14f whichare each conductively electrically coupled to an electrical terminal 16through crimped, bent-over ends 16a, 16b which form the portions of theelectrical terminals that protrude through openings 12a provided ininsulating substrate 12 for receiving the electrical connecting ends ofthe terminals 16. The projections 16a, 16b are bent over and firmlypressed into the associated terminal pad 14e, 14f to assure theprovision of a good electrical conductive path. The size of the pads isnot critical and the pads may be eliminated so long as the terminal endsprovided are sufficient for electrical and mechanical engagement with anassociated terminal 16.

An insulating resin 18 coats the exposed surfaces of projections 16a,16b and the heater element to provide good electrical insulation, aswell as corrosion resistance, therefor. In addition, the conformalinsulating material wicks into the holes containing terminals 16imparting significant structural strength to the joined terminals andthe insulating substrate as well as providing the desired electricalinsulation and corrosion resistance. The terminals are removablyinserted into a conventional electrical outlet, not shown, having twoelongated slot-like openings to receive said terminals.

Making reference to FIG. 5, a production method will now be describedwhich lends itself to low cost production of a quality heating elementof superior electrical and mechanical strength and integrity.

The production method utilized is based upon the use of multiple imageprinting and processing which enables the simultaneous production of asignificant number of heating units.

The process steps include the following:

Making reference to FIG. 5, a substrate panel 100 is cut to a suitablesize which lends itself to economic production techniques. Utilizing a24×24 inch square panel 100 to produce heating elements of asubstantially square size shape of 1.25×1.25 inch square, the techniquepermits 361 such elements to be produced simultaneously per 24×24 inchsquare substrate 100. Smaller or larger size insulating substrates maybe utilized, if desired. The size of the substrate of the individualheating element subassemblies (note FIG. 1, for example) may also beadjusted, if desired.

Three locating or pinning holes 100a, 100b and 100c are drilled intopanel 100 to define a pair of datum lines L1 and L2 which areperpendicular to one another to provide repeatable reference points formounting the board 100 to equipment (not shown) for performingsuccessive processing steps, thereby assuring proper registration withthe equipment used in moving from one processing step to the next.

With the panel 100 in proper registration, resistor patterns aresimultaneously formed for each heater element unit utilizingconventional printed circuit techniques which, very briefly, typicallyinclude coating the entire insulating substrate with the polymerresistor material, coating the polymer resistor material with a etchresistant, covering the substrate with a pattern which, passes lightonly through regions of the resist which are to be etched away, etchingaway the areas of the resist exposed to light and thereby also etchingaway the polymer resistor material therebeneath and finally washing awaythe unexposed resist, leaving the desired polymer resistor patterns.

After the resistor patterns are formed, four holes are either punched ordrilled in each individual substrate to accommodate the terminals 16a,16b of the electrical contact terminals (see FIG. 1).

The substrate is then scored on both sides to provide the horizontal andvertical score lines S_(H) and S_(V).

Thereafter, a conductive contact terminal (i.e. blade) is inserted intoeach pair of holes provided for receiving same. The projections 16a, 16bof each conductive contact blade are firmly crimped, i.e. bent over andpressed into the surface of panel 100 containing the terminal pads ofthe resistor pattern to assure good electrical contact between eachterminal and an associated resistor terminal pad.

The insulating coating which is preferably any one of polyurethane,polymer, Dymax 984LUF or other materials having similar properties issprayed onto the surface of panel 11 bearing the resistor pattern,providing an electrical insulating coating for the resistor patterns aswell as the exposed conductive surfaces of the crimped projections 16a,16b. In addition, the coating material wicks into the openings receivingthe electrical terminals to firmly fill and seal said openings and theinterstices between the substrate 100 and the terminals 16, and therebyprovide significant structural strength to the joined terminals 16 andeach substrate 12. FIG. 2 shows the manner in which the insulatingmaterial has wicked into opening 12a to substantially fill any hollow oropen regions between one terminal 16 and substrate 12, as well asproviding an insulating coating and corrosion protecting coating overthe resistor pattern 14 and the projections 16a and 16b.

After the insulating material is dried, electrical tests are performedto assure satisfactory electrical continuity and to further assure thatthe magnitude of the current through the resistance-type heatingelements fall within an acceptable range.

Thereafter, the individual heating units 10 (see FIG. 1) are separatedfrom one another by breaking the units apart from one another along thescore lines S_(H) and S_(V), whereupon the individual units are ready tobe assembled into the finished product.

FIG. 4 shows an exploded view of the components of the heater of a scentgenerating unit comprised of heating unit 10, a scent module 40 and ahousing or cover 50. Cover 50 is shown in greater detail in FIGS. 3, 3aand 3b and is comprised of a front face 50a surrounded by four sidewalls 50b, 50c, 50d and 50e which define an open-ended hollow interiorfor receiving scent module 40. Elongated slots 51 are provided inhousing 50, said slots extending along front face 50a and side walls 50cand 50e. The housing 50 may be used with other vaporizable modules, ifdesired.

Interiors of the side walls 50b through 50e are each provided with ashoulder 50b-1 through 50e-1, said shoulders each supporting a marginaledge of the heating element substrate 12, FIG. 3b showing the manner inwhich one marginal edge of substrate 12 is supported by shoulder 50b-1.

The housing 50 is preferably a molded member or alternatively may bemachined in the configuration shown. The scent (or repellant) module 40is inserted into the mold member whereupon the heater unit is positionedso that its marginal edges are each supported by an associated shoulder50b-1 through 50e-1. The substrate may be secured to cover housing 50 bya suitable epoxy or glue or alternatively by application of heat or asolvent upon assembly of the components fusing the substrate and housingto one another thereby providing a finished unit which is quite ruggedand compact and neither has nor requires any moving or movable parts.The superior structural strength of the heater unit subassembly 10assures and enhances the integrity of the mechanical and electricalconnections therein providing a device which may be installed and usedsafely.

The flutes 40a, comprising a plurality of elongated grooves, provided inthe front face of module 40, cooperate with the housing and the openings51 in cover housing 50 to provide a chimney effect which facilitatesdelivery of the scented airborne vapors into the region surrounding unit30. More particularly, as vapors are emitted from a "top" end air entersinto the "bottom" end, creating the "chimney effect". The module 40 mayalternatively be formed of a vaporizable solid material for use as aninsect or pest repellant which may also incorporate a pleasing scent.

FIGS. 6a and 6b show still another preferred embodiment 30' of thepresent invention which utilizes a heating element subassembly 10'substantially similar to that shown, for example, in FIGS. 1 and 4 beingmodified only to provide a pair of locking protrusions P provided on oneface thereof. Module 40 is substantially the same type as shown in FIG.4. The cover housing 50' differs from the cover housing 50 of FIG. 4 inthat the shoulders 50b-1 through 50e-l are substantially eliminated,wall 50b' is a solid end wall while a portion of side wall 50e' isremoved as shown best in FIG. 6a and parallel side walls 50c' and 50d'are provided with grooves 50d'-1 and 50c'-1 which slidably receiveopposite parallel edges of the substrate 12. The substrate 12 is pushedinto the substrate receiving groove 50d'-1 and 50c'-1 in a directionshown by arrow A as shown in FIG. 6b which shows the substrate 12partially inserted. As the rounded protrusions P reach side wall 50e',their sloping edges P-1 slide along the edge of side wall 50e'.Ultimately, the protrusions P pass side wall 50e' whereupon the straightside P-2 of the protrusions P pass beyond the upper edge of side wall50e' snap-fittingly locking the heating unit subassembly into thehousing.

The electrical terminals 16 are formed from a pair of sheet-like members16-1 and 16-2 which are bent in half and pressed against one another.Each sheet-like conductive member carries one of the prongs 16a and 16b.If desired, each of these members 16-1 and 16-2 may be folded over uponitself to form the supports 16c, 16d shown in FIG. 2a to provideadditional support between the terminals and the underside of thesubstrate. However, it has been found that the combination of thecrimped projections 16a, 16b together with the insulating coating whichwicks into opening 12a has proven to be more than satisfactory inproviding a heating element of superior structural strength andstructural and electrical integrity, which may be used in scent and/orrepellant emitting devices capable of receiving replacement scentmodules.

A latitude of modification, change and substitution is intended in theforegoing disclosure, and in some instances, some features of theinvention will be employed without a corresponding use of otherfeatures. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with the spirit and scopeof the invention herein described.

What is claimed is:
 1. A method for producing an electrical heater,comprising the steps of:(a) forming an electrically resistive layer onone major surface of an electrically insulating substrate material, saidresistive layer being a material serving as a resistive-type electricalheating element; (b) forming at least two openings in said substrateadjacent to portions of said resistive layer; (c) providing at least twoelectrical terminals for releasable coupling with an electrical outlet,each having an insertion end shaped to be engaged in an associated oneof said openings in said substrate and a plug-in end for removableinsertion into an electrical outlet; (d) inserting first and secondelectrical terminals into said openings such that the insertion ends ofsaid terminals each protrude beyond the surface carrying said resistivelayer; (e) bending or crushing the protruding portions of said terminalssuch that they come in contact with said resistor material and form anelectrically conductive path between said terminals and said resistivelayer without the need for soldering; (f) coating said one major surfaceand the protrusions of said terminals with a liquid insulation materialapplied in sufficient quantity to cover the resistive layer and wickinto the interstitial spaces between said terminals and said substratematerial; (g) drying or otherwise curing said liquid insulation materialto form a solid coating of dielectric insulation over said resistivelayer, providing gas-tight sealing for said electrical contact andimparting structural support for said terminals and providing corrosionresistance for the insertion portions of said terminals.
 2. Anelectrical heating element formed by the process of claim
 1. 3. A methodfor simultaneously producing a plurality of heating elements comprisingthe steps of:(a) providing an insulating substrate; (b) simultaneouslyforming a plurality of layers of a resistive material at a plurality ofregularly spaced locations arranged on one surface of said insulatingsubstrate, said material serving as a resistor-type heating elementhaving a pair of connective ends; (c) forming sets of openings atlocations along said substrate which are in registry with an associatedheater element; (d) providing, for each heater element, two electricalterminals for releasable coupling with an electrical outlet, eachterminal having an insertion end shaped to be engaged in an associatedone of said openings in said substrate and a plug-in end for removableinsertion into an electrical outlet.
 4. The method of claim 3 furthercomprising the steps of:(h) forming score lines on at least one side ofsaid substrate panel whereby said score lines define the boundaries ofeach individual heating element; and (i) breaking each of the individualsubstrates apart from one another by bending the panel along the scorelines, causing the individual substrates to break away from one anotheralong said score lines.
 5. The method of claim 1 wherein step (e)further comprises spraying said insulation layer onto said substrate. 6.The method of claim 3 wherein step (e) further comprises spraying saidinsulation layer onto said substrate.
 7. A heating element comprising:aninsulating substrate having a resistance-type layer arranged in apredetermined pattern for use as an electrical heater provided on onemajor surface thereof, said layer having first and second terminal ends;sets of holes being provided in said substrate, each being in theimmediate vicinity of an associated one of said terminal ends; a pair ofelectrical conductive terminals extending outwardly from a major surfaceof said substrate opposite the surface on which said resistance layer isprovided, said terminals having projecting portions which are bent overand firmly pressed into intimate engagement with an associated one ofsaid terminal ends to provide an electrical conductive path between eachterminal and an associated terminal end; and an insulating layer beingprovided over said resistance layer and exposed surfaces of saidbent-over projections to provide an electrical insulation layer, saidinsulating layer being of a material causing the insulating layer towick into said openings and substantially fill the interstices betweensaid openings and said terminals impart structural strength to theterminals.
 8. The apparatus of claim 7 wherein said insulating layer isone of acrylate varnish, polyurethane and urethane acrylate.
 9. Theapparatus of claim 7 wherein said pattern is further comprised of atleast a pair of serpentine pattern portions spaced apart from oneanother and arranged on opposite sides of a line extending between saidterminals and being electrically connected to one another by patternconnecting portions.
 10. The heating element of claim 7 wherein eachterminal is provided with a pair of projections which are bent to extendin opposing directions along said substrate.